This invention relates to a process for covering or coating disk-shaped electric components with an insulating covering. The components have electric leads extending away from them.
One such process is disclosed in German Pat. No. 1,202,852. In that patent, the electrical component which is provided with leads is first dipped into a liquid and the wet surface of the component body is thereafter covered with a plastic powder. The plastic powder is melted and is hardened during a heat treatment. In this process, wetting of the leads by the liquid is reduced. But it cannot be completely avoided.
In another known process for covering a disk-shaped electric component, such as an electric capacitor, the component is dipped into a viscous synthetic resin covering or coating material until the edge of the disk from which the leads protrude is also covered with covering material. Due to the surface tension or the viscosity of the synthetic resin, it is necessary to immerse the component below the surface of the liquid. Due to this as well as to the forces of adherence, relatively prolonged wettings of the lead elements in the vicinity of the body of the component can, however, not be avoided.
If electric components that have been covered with an insulating covering by either of the above processes are inserted into the passage holes of printed circuits, the wetted or covered portions of the leads may extend through the passage hole so that dependable contacting with the leads, by soldering, for example, is prevented.
The electric component shown in German Utility Model No. 7,709,932 has stops for limiting the depth of insertion of its insertion leads. Dependable contacting by soldering is assured by a bead-like widening of the leads. But, due to the finite length of the distance from the bead to the component, high-frequency behavior of the component is adversely affected, particularly in the case where the component is a capacitor.